A study revealed that there may possibly be two extra neurons in the brain of males that drive them to be obsessed about sex, and that these neurons may not be present in the brain of females. Scientists examined the nervous system of male nematode worms and found two extra neurons called mystery cells of the male (MCM).
Some scientists have been worried about the significance of this study, but the researchers of the study said that the discovery is essential in understanding the psychological and physiological factors that affect males' drive for copulation. In fact, nematode worms or the Caenorhabditis elegans have similar biological aspects with humans, scientists say.
In a study published in the journal Nature, researchers said that learning about behavior from the single-cell level would be helpful in studying the behavior of higher organisms such as humans. Although researchers haven't fully delved into the idea, they believe that human males also have the MCM.
Scientists say that most organisms' sexual behavior is affected by cognitive processes such as learning. With the MCM, the male nematode worm learns to prioritize its drive for mating and forget all other things. This finding connects differences in sexual behavior among different organisms.
The study also mentioned that the MCM develops during the male nematode worm's sexual maturation which only happens at the help of specialized cells called glia.
Researchers used classical conditioning in finding how male nematode worms prioritized mating. The group conditioned the male and hermaphrodite nematode worms to dislike salt by associating it with starvation. Hermaphrodite nematode worms do not need mates to reproduce.
For the males, they added mates to a salted arena. The male nematode worms chose to endure the salty arena for their mates, but when their MCM was removed, the result was otherwise. The male nematode worms didn't bother moving near their mates anymore. Scientists said that this proved how the MCM influenced the nematode worms' choice.
The MCMs are found near neurons that are densely connected. "They seem to have an important position in the circuitry," said Bill Schafer, who studies nematode worms at the University of Cambridge.
Researchers will focus next on how the MCMs contribute to the part of the nematode worm's brain that controls learning, and how they feed into sex differences.
"In terms of being able to get a detailed understanding, it's much easier when you've got hundreds of cells rather than hundreds of billions of cells," added Schafer.
Meanwhile, co-author of the study, Professor Scott Emmons said that although the study is carried out in a nematode worm, it still provides us with a standpoint that helps us potentially understand the variety of gender identification, human sexuality and sexual orientation.
Photo : J.K. Califf | Flickr